1. Field of the Invention
The invention relates to a method and to a system for transmitting data in a motor vehicle by wireless communication, in which the data from a first transmitting data node are divided and are transmitted via at least two different communication routes to a second receiving data node and are reassembled upon reception.
2. Related Art
Usually, in current vehicles, components are connected to one another almost exclusively by cable since the susceptibility to interference of wireless communication links frequently does not permit reliable communication between the individual components in the vehicle.
Even ultra-wide-band communication (UWB communication), which, due to its great frequency bandwidth is very resistant to interference in the frequency band, as a rule, can not provide sufficiently reliable communication between vehicle components. Here, too, a communication link between two components can be interrupted if, e.g., an interconnecting node fails or a wide-band attenuator, for example in the form of a metal plate, is inserted between two interconnecting nodes. This may happen quite easily since the conditions for wireless communication can change continuously in any vehicle, for example due to different loading.
For this reason, data transmission in motor vehicles is in most cases wire-connected, in which direct connecting lines between the individual components provide for corresponding communication. In some cases, communication bus systems are also used in which the information of the individual components is exchanged via a common bus system. However, such a bus system is expensive to install and maintain since, in most cases, new components must be registered in the bus system. On the other hand, installing individual cable harnesses to all components in each case is expensive and contributes to a distinctly higher vehicle weight due to the copper lines used in most cases. Furthermore, it impairs the subsequent installation of components since cable harnesses can still only be pulled through with great effort after the completion of the vehicle.
DE 600 17 724 T2 describes a known system and method for transmitting data via a number of possible communication paths which have different features. During the data transmission, the features of the possible communication paths are detected and the data flow is divided into at least two of these communication paths on the basis of this information and on an optimization condition given by the user, for example in the form of data packets. In the receiving unit, the data flow transmitted via the different communication paths is joined again. Suitable information items, on the basis of which the data flow is divided, are prices and speed of the communication paths, permitted data packet sizes, transportation time, information items relating to interposed transmitting units and priorities predetermined by the user. In this manner the capacities of the available communication systems are to be better utilized. Correspondingly, the various communication paths to be used are, for example, HSCSD, GPRS, Bluetooth, WLAN or the like.
In spite of the better utilization of capacity of the available communication paths, however, the security of transmission is not improved. In contrast, gaps can occur during the joining of the data from the various data packets which lead to the loss of data. The transmission can not, therefore, be used reliably for security-related data.